This invention relates to an odor counteractant to be applied as a coating on a substrate to control or modify odors resulting from the use of the substrate in contact with malodorous material and moisture. The invention further relates to the method of forming and using a macroemulsion incorporating the counteractant and to a product comprising the macroemulsion. In particular, the invention relates to the control of odors associated with the use of pet litter.
In the past, attempts have been made to control the odor in particulate pet litter by spraying an odor-modifying material directly on the litter. The odor-modifying material gave off its own odor, which was more pleasing than the odor resulting from normal use of the litter by pets, but the effect of the odor-modifying material dissipated rather soon.
An improved odor-modifying material described by Colborn et al. in U.S. Pat. No 4,407,231 was produced by encapsulating fragrance oil as an odor counteractant in microcapsules and spraying those microcapsules on the particles of litter. The microcapsules were frangible, and the typical digging or scratching action indulged in by the pet, especially a cat, using the litter broke some of the microcapsules with each use, releasing some of the fragrance to counteract the unpleasant odors resulting from pet excreta. This same frangibility required in a certain amount of microscapsule breakage in handling and transportation of the containers of treated litter, which was not altogether bad, because it released a small amount of the fragrance, which would be sensed by the pet owner when opening the container of litter.
However, in actual use, it is desirable to have no further odor counteractant released until the pet uses it. When that does happen, it is not only essential that some of the microcapsules be broken, but it is further desirable that the amount of odor counteractant released be generally proportional to the need, which means generally proportional to the quantity of excreta rather than to microscapsule breakage. Breakage by mechanical scratching action is proportional to the activity of the animal and not necessarily to the amount of malodorous material that needs to be counteracted.
This further requires that the odor counteractant be carried by material that is soluble in pet urine to release the counteractant, whether the pet paws the litter intensely or little or not at all. Microcapsules, as used heretofore, are not very soluble and, thus, the fragrance oils contained in them are not released in proportion to need as specifically as is desired.